| (19) |
 |
|
(11) |
EP 0 962 478 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
27.12.2000 Bulletin 2000/52 |
| (43) |
Date of publication A2: |
|
08.12.1999 Bulletin 1999/49 |
| (22) |
Date of filing: 01.06.1999 |
|
|
| (84) |
Designated Contracting States: |
|
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
|
Designated Extension States: |
|
AL LT LV MK RO SI |
| (30) |
Priority: |
01.06.1998 JP 15160998
03.06.1998 JP 15446298
04.06.1998 JP 15605598
12.06.1998 JP 16520198
18.06.1998 JP 17141298
|
| (71) |
Applicant: MITSUBISHI GAS CHEMICAL COMPANY, INC. |
|
Chiyoda-ku, Tokyo (JP) |
|
| (72) |
Inventors: |
|
- Nagai, Satoshi
22 Wadai, Tsukuba-shi, Ibaraki (JP)
- Kondo, Osamu
22 Wadai, Tsukuba-shi, Ibaraki (JP)
- Yoshida, Shu
22 Wadai, Tsukuba-shi, Ibaraki (JP)
- Sasaki, Makoto
22 Wadai, Tsukuba-shi, Ibaraki (JP)
- Konishi, Takashi
22 Wadai, Tsukuba-shi, Ibaraki (JP)
- Fujimori, Takayasu
22 Wadai, Tsukuba-shi, Ibaraki (JP)
|
| (74) |
Representative: HOFFMANN - EITLE |
|
Patent- und Rechtsanwälte Arabellastrasse 4
81925 München
81925 München (DE) |
|
| |
|
| (54) |
Process for producing aromatic/aliphatic copolycarbonate |
(57) Processes for producing an aromatic/aliphatic copolycarbonate which has excellent
impact resistance, excellent heat resistance, a high Abbe's number, a low photoelastic
coefficient, and an excellent color tone.
An aromatic/aliphatic copolycarbonate having a nitrogen content of 9 ppm or lower
is produced from an aliphatic dihydroxy compound having a nitrogen content of 10 ppm
or lower.
An aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound
having an iron content of 1 ppm or lower.
An aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound
having a content of aldehyde groups and/or formyl groups of 100 ppm or lower.
An aromatic/aliphatic copolycarbonate is produced by subjecting an aromatic dihydroxy
compound and an aliphatic dihydroxy compound having a content of free chlorine of
5 ppm or lower to polycondensation with heating and melting.
An aromatic/aliphatic copolycarbonate is produced from an aliphatic dihydroxy compound
which has a melt Hazen unit of 40 or smaller after having been maintained at 260°C
for 5 hours in the air.
